OpenShift stabilisation tracker for (missing) support in the MCO #2279

Created originally in Butane by @travier: coreos/butane#719

We currently need to revert / disable support for multiple configuration elements in the OpenShift spec for each release due to missing support in the MCO. This issue is here to track them to not forget them when we do a spec stabilization.

Missing support for GRUB config

Support was added to the FCOS 1.5.0 spec but is not supported by the MCO and muss thus be removed from the OpenShift spec.

See: coreos/butane#515

Missing support for special mode bits (setuid, setgid, sticky bit)

Support was added in Ignition spec 3.6.0 but is not supported by the MCO and muss be removed from the OpenShift spec.